The present invention relates to a molybdenum-based alloy which is improved in mechanical strength, hot workability and so on.
Molybdenum-based alloys have excellent stability at high temperatures in vacuums or in inert or reducing atmospheres, and are currently used as adiabatic materials. The field of application of molybdenum-based alloys is recently spreading to nuclear-related fields. However, with conventional molybdenum-based alloys, when they are heated to the recrystallization temperature, the grain become coarse, and when they are cooled to ambient temperature, they show poor ductility and brittle fracture occurs at the grain boundaries. Conventional molybdenum-based alloys further have the drawbacks of poor hot workability and significant embrittlement upon irradiation with neutrons. In order to solve these problems, it has been proposed to prepare a molybdenum-based alloy containing a small amount of vanadium (Japanese Patent Publication No. 33,084/1978). According to this alloy, vanadium is present in the form of a solid solution to increase the mechanical strength of the alloy and to clean the grain boundaries by reaction of vanadium with the grain boundary impurities. It is also proposed to prepare a molybdenum-based alloy containing carbon to improve the deoxidation effect (Japanese Patent Disclosure No. 47,511/1976).
Although the addition of vanadium or carbon as proposed above solves the problems to a certain extent, satisfactory results have not been obtained so far and further improvements in molybdenum-based alloys have been desired.